Centering attachment for cylinder-boring device

ABSTRACT

A head for mounting on a boring bar supported for rotation about a reference axis and shiftable along that axis. The head includes mounting structure for mounting a cutting tool thereon and is provided with a plurality of arcuate centering arms seated in recess areas therefor extending and spaced about the periphery of the head. One set of corresponding ends of the arms are pivotally supported in the corresponding recess areas for swinging of the other set of ends of the arms between retracted positions at least substantially received within the recess areas therefor and extended positions swung outwardly of the outer surfaces of the head for engagement with the walls of a bore formed in a workpiece to center the bore relative to the axis of rotation of the head. The head further includes means operative to simultaneously and equally swing the arms between extended and retracted positions.

United States Patent Nathan Dale Holleman 12619 82nd Ave. N., Seminole, Fla. 33540 [21] Appl. No. 9,471

[22] Filed Feb. 10, 1970 [45] Patented Dec. 28, 1971 [72] Inventor [54] CENTERING ATTACHMENT FOR CYLINDER- Primary Examiner-Gerald A. Dost Attorneys-Clarence A. OBrien and Harvey B. Jacobson ABSTRACT: A head for mounting on a boring bar supported for rotation about a reference axis and shiftable along that axis. The head includes mounting structure for mounting a cutting tool thereon and is provided with a plurality of arcuate centering arms seated in recess areas therefor extending and spaced about the periphery of the head. One set of cor responding ends of the arms are pivotally supported in the corresponding recess areas for swinging of the other set of ends of the arms between retracted positions at least substantially received within the recess areas therefor and extended positions swung outwardly of the outer surfaces of the head for engagement with the walls of a bore formed in a workpiece to center the bore relative to the axis of rotation of the head. The head further includes means operative to simultaneously and equally swing the arms between extended and retracted positions.

PATENIEB DEB28 :sn

SHEET 1 [1F 2 Nathan Dale Hal/amen BY WW 19M C ENTERING ATTACHMENT lFOR CYLINDER-BORING DEVICE The attachment of the instant invention is designed to be utilized on substantially all boring bars or spindles. However, the attachment is primarily designed for use in conjunction with boring machines designed specifically for reboring the cylinders of small air-cooled combustion engines.

The centering device consists of central pinion gear in mesh with gear segments on corresponding ends of three locating fingers swingably supported from a body in which the pinion gear is journaled and rotation of the pinion gear is effective to cause the free ends of the locating fingers or arms to be swung outwardly of the body into contact with the surfaces of a bore to be refinished. Simultaneous contact of the positioning fingers or arms with the surfaces of the bore to be refinished will cause the cylinder in which the bore is formed to be centered relative to the rotational axis of the boring bar or spindle of the boring machine from which the cylinder is supported. After the cylinder has once been properly positioned on the boring machine, it may be clamped in position and the positioning arms or fingers may be retracted.

The main object of this invention is to provide a centering head for the spindle or boring bar of a boring machine and which may be utilized to ensure proper centering of a bore to be refinished by the boring machine.

Another object of this invention, in accordance with the immediately preceding object, is to provide a centering head also including means by which a cutting tool for reboring a cylinder on the boring machine by the positioning fingers of the centering head will automatically properly center the cylinder relative to the axis about which the cutting tool also supported from the centering head will be subsequently swung in resurfacing the associated bore.

Still another object of this invention is to provide an attachment in accordance with the preceding objects and which may be readily supported from substantially all boring machine spindles or boring bars.

A final object of this invention to be specifically enumerated herein is to provide a boring bar centering head in accordance with the preceding objects which will conform to conventional forms of manufacture, be of simple construction and easy to use so as to provide a device that will be economically feasible, long lasting and relatively trouble free in operation.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a side elevational view of the upper portion of a boring machine having a cylinder barrel of an air-cooled engine supported therefrom and with the centering head of the instant invention operatively mounted on the boring bar of the machine, parts of the machine and cylinder barrel being broken away and illustrated in vertical section;

FIG. 2 is an enlarged horizontal sectional view taken substantially upon the plane indicated by the section line 22 of FIG. 1;

FIG. 3 is a perspective view of the centering head;

FIG. 4 is a vertical sectional view taken substantially upon the plane indicated by the section line 4--4 of FIG. 3;

FIG. 5 is a horizontal sectional view taken substantially upon the plane indicated by the section line 66 of FIG. 4;

FIG. 7 is a horizontal sectional view taken substantially upon the plane indicated by the section line 77 of FIG. 4; and

FIG. 8 is a horizontal sectional view taken substantially upon the plane indicated by the section line 88 of FIG. 4.

Referring now more specifically to the drawings, the numeral 10 generally designates a boring machine whose upper portion 12 defines a sleeve mount on whose upper end an apertured mounting plate 14 is secured by means of fasteners 116. The lower ends of a pair of upstanding threaded standards 18 are secured through opposite ends of the mounting plate 14 and a pressure head 20 is supported from the upper ends of the standards 18 for vertical adjustment therealong by means of nuts 22. The pressure head -20 has a clamp screw 24 threadedly supported therefrom and the lower end of the clamp screw 24 includes a swivel pad 26.

The boring machine 10 includes a rotatable boring bar or spindle which is vertically shiftable both during and independent of rotation of the boring bar and the upper end of the boring bar or spindle includes a blind bore 28 which is threaded and includes a smooth counterbore 30.

The preceding description is to be understood as that of a conventional form of boring machine. The centering head of the instant invention is referred to in general by the reference numeral 32 and has been designed for use in conjunction with the machine 10 as well as other machines of similar construction and operation.

The head 32 includes a cylindrical body referred to in general by the reference numeral 34, a mounting fitting 36 and a top or cover plate 38. The lower end of the cylindrical body includes a downwardly opening cylindrical recess 39 concentric with the center axis of the body 34 and the fitting 36 includes a cylindrical head 40 which is seated and secured within the recess 39 by means of threaded fasteners 42. The lower end of the mounting fitting 36 defines an externally threaded shank portion 44 and the mounting fastener 36 includes a cylindrical shoulder 43 between the shank portion 44 and the head 40.

The mounting fitting 36 is threadedly engaged in the blind bore 28 with the shoulder 43 seated in the counterbore 30 and the undersurface of the head 40 disposed outwardly of the shoulder 43 abutted against the upper end of the boring bar 26.

The body 34 includes a transverse slot 46 extending therethrough and which opens downwardly into the recess 39 and those portions of the body 34 embracing the head 40 and in vertical registry with the ends of the slot or groove 46 are removed as at 48, see FIG. 3. The body 34 includes a pair of threaded transverse bores 52 which open into the slot 46 and have setscrews 54 and 56 threadedly engaged therein. A tool bar 58 is provided and is secured in longitudinally shifted position within the slot 46 by means of the setscrews 54 and 56.

The upper end of the body 34 has an axial bore 60 formed therein including an upper end counterbore 62. An axle pin 64 is provided and includes a diametrically reduced lower end portion 66 which is rotatably received in the bore 60 and a main gearwheel 68 is mounted on the axle pin 64 and received within the main recess 62. Further, the body 34 includes three equally circumferentially spaced secondary bores 70 formed therein. The bores 70 are spaced equally about and radially outwardly from the bore 60 and include counterbores 72 which open into the adjacent portions of the counterbore or recess 62. Three axle shafts 74 have their lower ends journaled in the secondary bores 70 and a thrust-bearing washer 76 is disposed about each axle shaft 74 in the bottom of the corresponding counterbore or recess 72. A secondary gearwheel 78 is journaled on each axle shaft 74 above the corresponding washer 76 and the enlarged ends 80 of three arcuate centering arms or fingers 82 are pressed on the upper ends of the axle shafts 74 and keyed to the corresponding secondary gearwheel 78 by means of pins 84. In addition, three tubular spacers 86 are provided in registry with threaded blind bores 88 formed in and about the upper end of the body 34 and a plurality of headed fasteners 88 are secured through the cover plate 38 and the spacers 86 and threadedly engaged in the bores 88 to secure the cover plate 38 over the upper end of the body 34.

It will be noted that the cover plate 38 has a central bore 90 formed therein and that the upper end 92 of the axle pin 64 projects upwardly through the bore 90 and is provided with a diametric kerf 94 engageable by a screwdriver blade.

it may thus be seen that after the centering attachment or boring head 32 is secured to the upper end of the boring bar 26 the arcuate fingers or arms 82 may be extended to the dotted line positions thereof illustrated in FIG. 5 of the drawings and retracted to the solid line positions thereof illustrated in FIG. 5 by oscillation of the axle pin 64, the shoulder 43 and the shank portion 44, is cylindrical in configuration and without components thereof which do not conform to the cylindrical outer surface of the body 34. Further, the attachment 32 may be utilized in conjunction with mounting fittings such as fitting 36 but of slightly different configuration adapting the head 32 to be utilized on other boring bars.

In operation, after the attachment or head 32 has been secured to the upper end of the boring bar 26, the tool bar 58 is secured in the desired position within the slot or channel 46 by means of the setscrews 54 and 56. Then, with the boring bar 26 lowered so that the tool bar 58 is disposed below the upper surface of the mounting plate 14, a mounting ring or sleeve 92 may be disposed on the upper surface of the mounting plate 14 about the opening 94 formed therein in registry with the vertical opening 96 defined by the upstanding sleeve mount or member 12. Then, a cylinder barrel 98, which may include a lower extension 100, is placed over the ring 92 with its lower cylinder extension 100 projecting down into the positioning ring 92. Of course, the mating surfaces of the mounting plate 14, positioning ring 92 and lower mounting flange 102 of the cylinder barrel 98 are cleaned of any foreign material so as to afford full surface-to-surface contact. Further, if the barrel 98 does not include the extension 100, the lower end of the barrel is placed on top of the ring 92. Thereafter, the boring bar 26 is raised so as to position the tool bar 58 closely beneath the lower extension 100 of the cylinder barrel 98 and with the fingers or arms 82 received upwardly in the bottom end of the bore 104 extending through the barrel 98. Then, any suitable bridge such as bridge 106 is positioned over the upper end of the barrel 98 and the screw 24 is lowered until the swivel pad 26 is almost in contact with the upper surface 108 of the bridge 106. Thereafter, a long-handle screwdriver is inserted downwardly through the upper end of the cylinder barrel 98 with its blade engaged in the kerf 94 and the screwdriver is turned so as to extend the fingers or arms 82 with their outer ends in contact with adjacent portions of the bore 104. Torsional pressure is maintained on the screwdriver and the barrel 98 is shifted and perhaps slightly rotated so as to ensure that the outward pressure on the surfaces of the bore 104 will accurately center the bore 104 relative to the axis of rotation of the boring bar 26. Then, while torsional pressure is maintained on the screwdriver, the screw 24 is lowered so as to clamp the barrel 98 between the bridge 106 and the positioning ring 92. Thereafter, the screwdriver may be rotated in the opposite direction so as to retract the fingers 82 to the solid line position thereof illustrated in FIG. 5 of the drawings and thereafter the boring machine may be actuated to rotate the boring bar 26 and thereby swing the tool bar 58 through a circular path. As the boring bar 26 is gradually raised during its rotation, the tool bar 58 engages and resurfaces the bore 104. After the boring bar 26 has been raised so as to position the tool bar 58 above the upper end of the barrel 98, the operation of the boring machine 10 is terminated and the screw 24 is raised so as to enable removal of the bridge 106. Thereafter, the barrel 98 is removed being sure that the outer end of the tool bar 58 does not engage the resurfaced bore of the barrel 98 during removal of the latter.

It will be noted that the washers 76 function as springs and urge the secondary gear wheels 78 upwardly in the counterbore 72 in order that there is no direct sliding contact between the undersurface portions of the arms or fingers 72 and the upper end face of the body 34. Further, the vertical extent of the spacers 86 is slightly greater than the thickness of the arms 82 whereby the tightening of the fasteners 88 during securement of the cover plate 38 to the body 34 will not bind the arms or fingers 82 between the body 34 and the cover plate 38. Also, from FIG. 5 of the drawings it will be noted that the inner portions of the enlarged ends of the arms 82 overlie the adjacent peripheral portions of the main gearwheel 68 and thereby retain the latter against upward axial displacement in the recess or counterbore 62.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A head for the first advanced end of a rotatable boring bar, said head including a body defining front and rear ends and a center longitudinal axis, said head including means adapted to secure said head to said bar with said center axis coinciding with the axis of rotation of said bar, said head including means for mounting a cutting tool thereon and a plurality of generally radially outwardly opening and circumferentially spaced and extending arcuate recess areas, a plurality of elongated arcuate centering arms including one set of corresponding ends pivotally mounted from said body in one set of corresponding ends of said arcuate recess areas for swinging about axes spaced about and generally paralleling said center axis between retracted positions with said arms at least substantially fully received in said recess areas and extended positions with the other set of corresponding ends of said arms swung outwardly of the outer surfaces of said body for engagement with the walls of a bore into which said bar is to be advanced, said head further including actuating means operatively connected with said arms for simultaneously and equally adjustably swinging said arms between their retracted and extended positions.

2. The combination of claim 1 wherein said body includes a center bore formed therein opening outwardly of said front end and concentric with said axis, the forward end of said bore including an enlarged main counterbore, said body having a plurality of secondary bores formed therein, said secondary bores opening outwardly of said front end, being spaced equally radially outwardly of said center bore and generally paralleling the latter and including forward end secondary counterbores opening laterally inwardly into said main counterbore and spaced inwardly from the adjacent outer peripheral portions of said body, a main gearwheel seated in said main counterbore and including a concentric axially outwardly projecting shaft portion journaled in said main bore inwardly of said main counterbore, said one set of ends of said arcuate recess areas opening inwardly into said secondary counterbores, said one set of ends of said arms including gearwheel segments disposed in said secondary counterbores, meshed with said main gearwheel and including bores formed therethrough aligned with said secondary bores, a plurality of apertured spacers disposed on said front end about said main counterbore and between said secondary counterbores, and an apertured cover plate secured over said front end by fasteners secured thercthrough, through said spacers and to said body, said actuating means comprising said main gearwheel.

3. The combination of claim 2 wherein said main gearwheel includes an axial extension projecting outwardly through said cover plate, the outer end of said extension being adapted to be engaged by a tool for applying rotational torque thereto.

4. The combination of claim 1 wherein said one set of arms include gearwheel segments spaced about and outwardly of said center axis, said actuating means including a main gearwheel journaled from said body for rotation about said center axis and meshed with said gearwheel segments.

5. The combination ofclaim 1 wherein said body includes a center bore formed therein opening outwardly of said front end and concentric with said axis, the forward end of said bore including an enlarged main counterbore, said body having a plurality of secondary bores formed therein, said secondary bores opening outwardly of said front end, being spaced equally radially outwardly of said center bore and generally paralleling the latter and including forward end secondary counterbores opening laterally inwardly into said main counterbore and including a concentric axially outwardly projecting shaft portion journaled in said main bore inwardly of said main counterbore, said one set of ends of said arcuate recess areas opening inwardly into said secondary counterbores, said one set of ends of said arms including gearwheel segments disposed in said secondary counterbores, meshed with said main gearwheel and including bores formed therethrough aligned with said secondary bores, a plurality of apertured spacers disposed on said front end about said main counterbore and between said secondary counterbores, and an apertured cover plate secured over said front end by fasteners secured therethrough, through said spacers and to said body, said actuating means comprising said main gearwheel, said one set of ends of said arms including apertured enlarged end portions, said gearwheel segments being secured to corresponding sides of said enlarged end portions, said cover plate overlying the other sides of said enlarged end portions.

6. Tile combination of claim wherein said main gearwheel includes an axial extension projecting outwardly through said cover plate, the outer end of said extension being adapted to be engaged by a tool for applying rotational torque thereto.

7. The combination of claim 1 wherein said body is cylindrical and the outer surfaces of said arms, when the latter are recessed, are generally flush with the adjacent outer surfaces of said body.

8. The combination of claim 1 wherein said means for mounting a cutting tool on said body is spaced toward the rear end thereof from said arms.

9. A head for the first advanced end of a rotatable boring bar, said head including a body defining front and rear ends and a center longitudinal axis, said body including means on its rear end adapted to secure said head to said bar with said center axis coinciding with the axis of rotation of said bar, said head further including means adjacent said rear end for mounting a cutting tool thereon and a plurality of elongated centering arms having one set of ends pivotally mounted from said body for oscillation about axes spaced about and generally paralleling said center axis between extended and retracted positions with the other set of ends relatively extended and retracted, respectively, relative to said body, said body also including actuating means operatively connected with said arms for simultaneously and equally adjustably swinging said arms between their extended and retracted positrons.

10. THe combination of claim 9 wherein said means for mounting a cutting tool on said body is spaced toward the rear end thereof from said arms. 

1. A head for the first advanced end of a rotatable boring bar, said head including a body defining front and rear ends and a center longitudinal axis, said head including means adapted to secure said head to said bar with said center axis coinciding with the axis of rotation of said bar, said head including means for mounting a cutting tool thereon and a plurality of generally radially outwardly opening and circumferentially spaced and extending arcuate recess areas, a plurality of elongated arcuate centering arms including one set of corresponding ends pivotally mounted from said body in one set of corresponding ends of said arcuate recess areas for swinging about axes spaced about and generally paralleling said center axis between retracted positions with said arms at least substantially fully received in said recess areas and extended positions with the other set of corresponding ends of said arms swung outwardly of the outer surfaces of said body for engagement with the walls of a bore into which said bar is to be advanced, said head further including actuating means operatively connected with said arms for simultaneously and equally adjustably swinging said arms between their retracted and extended positions.
 2. The combination of claim 1 wherein said body includes a center bore formed therein opening outwardly of said front end and concentric with said axis, the forward end of said bore including an enlarged main counteRbore, said body having a plurality of secondary bores formed therein, said secondary bores opening outwardly of said front end, being spaced equally radially outwardly of said center bore and generally paralleling the latter and including forward end secondary counterbores opening laterally inwardly into said main counterbore and spaced inwardly from the adjacent outer peripheral portions of said body, a main gearwheel seated in said main counterbore and including a concentric axially outwardly projecting shaft portion journaled in said main bore inwardly of said main counterbore, said one set of ends of said arcuate recess areas opening inwardly into said secondary counterbores, said one set of ends of said arms including gearwheel segments disposed in said secondary counterbores, meshed with said main gearwheel and including bores formed therethrough aligned with said secondary bores, a plurality of apertured spacers disposed on said front end about said main counterbore and between said secondary counterbores, and an apertured cover plate secured over said front end by fasteners secured therethrough, through said spacers and to said body, said actuating means comprising said main gearwheel.
 3. The combination of claim 2 wherein said main gearwheel includes an axial extension projecting outwardly through said cover plate, the outer end of said extension being adapted to be engaged by a tool for applying rotational torque thereto.
 4. The combination of claim 1 wherein said one set of arms include gearwheel segments spaced about and outwardly of said center axis, said actuating means including a main gearwheel journaled from said body for rotation about said center axis and meshed with said gearwheel segments.
 5. The combination of claim 1 wherein said body includes a center bore formed therein opening outwardly of said front end and concentric with said axis, the forward end of said bore including an enlarged main counterbore, said body having a plurality of secondary bores formed therein, said secondary bores opening outwardly of said front end, being spaced equally radially outwardly of said center bore and generally paralleling the latter and including forward end secondary counterbores opening laterally inwardly into said main counterbore and spaced inwardly from the adjacent outer peripheral portions of said body, a main gear wheel seated in said main counterbore and including a concentric axially outwardly projecting shaft portion journaled in said main bore inwardly of said main counterbore, said one set of ends of said arcuate recess areas opening inwardly into said secondary counterbores, said one set of ends of said arms including gearwheel segments disposed in said secondary counterbores, meshed with said main gearwheel and including bores formed therethrough aligned with said secondary bores, a plurality of apertured spacers disposed on said front end about said main counterbore and between said secondary counterbores, and an apertured cover plate secured over said front end by fasteners secured therethrough, through said spacers and to said body, said actuating means comprising said main gearwheel, said one set of ends of said arms including apertured enlarged end portions, said gearwheel segments being secured to corresponding sides of said enlarged end portions, said cover plate overlying the other sides of said enlarged end portions.
 6. THe combination of claim 5 wherein said main gearwheel includes an axial extension projecting outwardly through said cover plate, the outer end of said extension being adapted to be engaged by a tool for applying rotational torque thereto.
 7. The combination of claim 1 wherein said body is cylindrical and the outer surfaces of said arms, when the latter are recessed, are generally flush with the adjacent outer surfaces of said body.
 8. The combination of claim 1 wherein said means for mounting a cutting tool on said body is spaced toward the rear end thereof from said arms.
 9. A head for the first advancEd end of a rotatable boring bar, said head including a body defining front and rear ends and a center longitudinal axis, said body including means on its rear end adapted to secure said head to said bar with said center axis coinciding with the axis of rotation of said bar, said head further including means adjacent said rear end for mounting a cutting tool thereon and a plurality of elongated centering arms having one set of ends pivotally mounted from said body for oscillation about axes spaced about and generally paralleling said center axis between extended and retracted positions with the other set of ends relatively extended and retracted, respectively, relative to said body, said body also including actuating means operatively connected with said arms for simultaneously and equally adjustably swinging said arms between their extended and retracted positions.
 10. THe combination of claim 9 wherein said means for mounting a cutting tool on said body is spaced toward the rear end thereof from said arms. 